Which of the following reasons caused catastrophic coral bleaching and mass coral deaths in the Andaman and Nicobar Islands?

The correct answer is Option 1

Key Points

•  Increase of 2°C temperature in the Indian Ocean

  • Coral bleaching occurs when corals expel the zooxanthellae algae living in their tissues due to environmental stress, mainly temperature rise. This leaves corals white and weak, making them vulnerable to death.

  • In the Andaman and Nicobar Islands, mass coral bleaching events have been primarily linked to rising sea surface temperatures (SSTs). A temperature increase of about 2°C above the average can cause severe bleaching.

• Events like El Niño and global warming have significantly contributed to this temperature rise, leading to catastrophic bleaching in these regions, especially in 1998, 2010, and 2016.

• Other options are incorrect because:

  • Heavy marine pollution (Option 2): While pollution can damage corals, it is not the primary cause of mass bleaching.
  • Increased industrial activities (Option 3): Industrialization affects corals locally but does not explain widespread bleaching across the Indian Ocean.
  • Decrease of temperature by 4°C (Option 4): A drop in temperature does not cause coral bleaching; instead, it is temperature rise that leads to it.

• Hence, The primary cause of catastrophic coral bleaching and mass coral deaths in the Andaman and Nicobar Islands is the increase of 2°C temperature in the Indian Ocean, making Option 1 the correct answer.